Reference Guide

D-3
Environmental and Technical Specifications
COM1 Serial Port
The COM1 Serial Port is located on the back panel of the VRC 6940. Table D-3 lists the pin
descriptions.
Table D-3. COM1 Serial Port Descriptions
Pin Name Signal Direction
1 GROUND GND IN
1
2 TRANSMIT DATA TXD OUT
1
3 RECEIVED DATA RXD IN
1
4 REQUEST TO SEND RTS OUT
1
5 CLEAR TO SEND CTS IN
1
6 DATA SET READY DSR IN
1
7 SIGNAL GROUND GND —
1
8 CARRIER DETECT DCD IN
1
9 Not used
10 Not used
11 REV CH OUT
1
12-19 Not used
20 DATA TERMINAL READY DTR OUT
1
21 Not used
22 RING INDICATOR RI IN
1
23 Not used
24 Reserved
2
25 Reserved
2
1
RS-232 signal
2
Symbol internal test signals